Scientists at the Indian Institute of Science have created a promising new material that can replace natural sand in construction. This development comes as a response to the growing scarcity of sand, a crucial component in building materials. The team is exploring methods to utilize carbon dioxide (CO2) captured from industrial waste gases, treated with excavated soil and construction waste, transforming it into a viable sand alternative. “This would not only reduce the environmental impact of construction materials but also impart properties that can enhance their use for construction,” they say.
Using CO2-treated construction waste in mortar, followed by curing in a CO2-rich environment, significantly accelerates the development of the material’s strength. This innovative process boasts a 20-22% increase in the material’s compressive strength. Additionally, injecting CO2 into clay soil, commonly found at construction sites, improves its interaction with cement and lime. This not only stabilizes the clay but also enhances its overall engineering performance.
They’ve explored incorporating captured CO2 into excavated soil to create cement-lime-soil composites, potentially replacing up to half of the fine aggregates typically used in mortar. This technique promotes the formation of calcium carbonate crystals, leading to improved strength and reduced pore space. Exposing these materials to CO2 further accelerates curing and increases early-age strength by 30%.
The researchers have also developed 3D-printable materials using stabilized excavated soil combined with binders like cement, slag, and fly ash. These materials offer superior printability, potentially reducing the need for cement and sand by up to 50% each.
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